An optical image stabilizer (OIS) module is an image stabilization module that performs a function of correcting a tremor, etc. when photographing is performed by a camera. As the spread of a smart phone, a tablet PC, etc. has recently been extended, the OIS module built in a conventional digital camera, etc. is also built in a camera module of a portable terminal.
When the OIS module is built in the camera module, it is most important to have minimum influence on the elasticity of an actuator (such as spring) shaking an auto focusing (AF) module in the direction of X- and Y-axes. By doing so, tremor correction can be performed suitable for a change in the angular velocity of a gyro sensor mounted in a cellular phone, etc.
The OIS module is generally divided into a lens shift method of moving a lens in the horizontal direction, a sensor shift method of moving an image sensor in the horizontal direction, a module tilt method of the AF module in the horizontal direction, etc. according to an object to be moved in the direction of the X- and Y-axes.
The lens shift method is a method of additionally shaking a lens unit moving in the direction of a Z-axis by an AF module in the direction of the X- and Y-axes, and a space in which the lens unit can be shaken in the direction of the X- and Y-axes is required in the inside of the AF module. Since the lens shift method can be configured by connecting a flexible printed circuit board (FPCB) to the AF module, there is no serious limitation in connecting a circuit board to the AF module. However, the lens unit is shaken in the horizontal direction in the inside of the AF module, and therefore, the optical axis of an optical system may be shaken.
On the other hand, since the module tilt method is a method of shaking the AF module itself in the direction of the X- and Y-axes, the optical axis of the optical system is maintained. Thus, when the tremor correction is performed, the module tilt method shows superior performance as compared with other methods.
However, in the module tilt method, the entire AF module should be shaken in the direction of the X- and Y-axes, and hence the AF module should be floated in a housing of the camera module. Accordingly, it is difficult to connect the FPCB to the AF module. This is because the conventional simple connection of the FPCB to the AF module has influence on the elasticity of an OIS actuator in the process in which the AF module moves in the horizontal direction.